1. Field of the Invention
The present invention relates to a video recording apparatus, a video recording system, and a video recording method which have a variable recording frame rate number in accordance with a condition.
2. Description of the Related Art
For an anticrime purpose and a purpose of resolving a crime case, it becomes general to place a monitoring system including a monitor camera at a bank, a convenience store, or a condominium building, etc., and such a monitoring system becomes popular recently. According to such a monitoring system, it is typical that, as a measure of precaution, videos are always recorded, and a sensor is installed at a predetermined location, and videos are recorded at a high frame rate before and after the generation of an alert with an alerting signal which is generated when the sensor detects an incident being as a trigger (see, for example, JP 2002-118822 A). A video recording apparatus disclosed in JP 2002-118822 A includes a ring buffer that temporarily stores videos (pre-frames) before and after the generation of an alert by several frames, and performs recording at a low frame rate as a normal recording mode through this ring buffer in a non-alerting condition (hereinafter, referred to as a normal condition). Moreover, when an alert is generated, the video recording apparatus changes the mode to the alerted recording mode, and keeps recording the videos (pre-frames) stored in the ring buffer and other videos (post-frames) after the alerting at a high frame rate until the trigger signal is subjected to a timeout processing.
According to the video recording apparatus disclosed in JP 2002-118822 A, however, the ring buffer stores the videos at the maximum frame rate number under any conditions, and thus the ring buffer is not utilized efficiently.
The present invention has been made in view of the above-explained circumstance, and it is an object of the present invention to efficiently utilize a ring buffer.